Ethanol vehicles pose a significant risk to human health, study finds
Posted on Wednesday, April 18, 2007 @ 22:05:00 GMT by vlad
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Ethanol is widely touted as an eco-friendly, clean-burning fuel. But if
every vehicle in the United States ran on fuel made primarily from
ethanol instead of pure gasoline, the number of respiratory-related
deaths and hospitalizations would likely increase, according to a new
study by Stanford University atmospheric scientist Mark Z. Jacobson.
His findings are published in the April 18 online edition of the
journal Environmental Science & Technology.
''Ethanol is being promoted as a clean and renewable fuel that will
reduce global warming and air pollution,'' said Jacobson, associate
professor of civil and environmental engineering. ''But our results
show that a high blend of ethanol poses an equal or greater risk to
public health than gasoline, which already causes significant health
damage.''
Gasoline vs. ethanol
For the study, Jacobson used a sophisticated computer model to
simulate air quality in the year 2020, when ethanol-fueled vehicles are
expected to be widely available in the United States.
''The chemicals that come out of a tailpipe are affected by a
variety of factors, including chemical reactions, temperatures,
sunlight, clouds, wind and precipitation,'' he explained. ''In
addition, overall health effects depend on exposure to these airborne
chemicals, which varies from region to region. Ours is the first
ethanol study that takes into account population distribution and the
complex environmental interactions.''
In the experiment, Jacobson ran a series of computer tests
simulating atmospheric conditions throughout the United States in 2020,
with a special focus on Los Angeles. ''Since Los Angeles has
historically been the most polluted airshed in the U.S., the testbed
for nearly all U.S. air pollution regulation and home to about 6
percent of the U.S. population, it is also ideal for a more detailed
study,'' he wrote.
Jacobson programmed the computer to run air quality simulations comparing two future scenarios:
-- A vehicle fleet (that is, all cars, trucks, motorcycles, etc., in the United States) fueled by gasoline, versus
-- A fleet powered by E85, a popular blend of 85 percent ethanol and 15 percent gasoline.
Deaths and hospitalizations
The results of the computer simulations were striking.
''We found that E85 vehicles reduce atmospheric levels of two
carcinogens, benzene and butadiene, but increase two
others-formaldehyde and acetaldehyde,'' Jacobson said. ''As a result,
cancer rates for E85 are likely to be similar to those for gasoline.
However, in some parts of the country, E85 significantly increased
ozone, a prime ingredient of smog.''
Inhaling ozone-even at low levels-can decrease lung capacity, inflame
lung tissue, worsen asthma and impair the body's immune system,
according to the Environmental Protection Agency. The World Health
Organization estimates that 800,000 people die each year from ozone and
other chemicals in smog.
''In our study, E85 increased ozone-related mortalities in the
United States by about 200 deaths per year compared to gasoline, with
about 120 of those deaths occurring in Los Angeles,'' Jacobson said.
''These mortality rates represent an increase of about 4 percent in the
U.S. and 9 percent in Los Angeles above the projected ozone-related
death rates for gasoline-fueled vehicles in 2020.''
The study showed that ozone increases in Los Angeles and the
northeastern United States will be partially offset by decreases in the
southeast. ''However, we found that nationwide, E85 is likely to
increase the annual number of asthma-related emergency room visits by
770 and the number of respiratory-related hospitalizations by 990,''
Jacobson said. ''Los Angeles can expect 650 more hospitalizations in
2020, along with 1,200 additional asthma-related emergency visits.''
The deleterious health effects of E85 will be the same, whether the
ethanol is made from corn, switchgrass or other plant products,
Jacobson noted. ''Today, there is a lot of investment in ethanol,'' he
said. ''But we found that using E85 will cause at least as much health
damage as gasoline, which already causes about 10,000 U.S. premature
deaths annually from ozone and particulate matter. The question is, if
we're not getting any health benefits, then why continue to promote
ethanol and other biofuels?
''There are alternatives, such as battery-electric, plug-in-hybrid
and hydrogen-fuel cell vehicles, whose energy can be derived from wind
or solar power,'' he added. ''These vehicles produce virtually no toxic
emissions or greenhouse gases and cause very little disruption to the
land-unlike ethanol made from corn or switchgrass, which will require
millions of acres of farmland to mass-produce. It would seem prudent,
therefore, to address climate, health and energy with technologies that
have known benefits. ''
Source: Stanford University
Via http://www.physorg.com/news96088035.html
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